An integrated approach to the taxonomy of the genus Verticillium

Abstract

The taxonomic relationship among 64 isolates of the genus Verticillium was investigated using a range of morphological, physiological and biochemical characters with particular reference to V. lecanii. Forty-five isolates pertaining to the V. lecanii complex were compared, including isolates from arthropods (entomopathogens), rust fungi (hyperparasites) and 'saprophytic' sources. Other Verticillium species from invertebrate, fungal and plant hosts were included in the study to explore relationships within the genus. By analysing 41 characters, similarities were calculated between isolates using Gower's coefficient, and dendrograms were derived by average linkage clustering. Six cluster groups were delimited: V. lecanii isolates (7), mostly from homopteran insects; hyperparasitic isolates (3), including one of Y. psalliofae, from rusts; V. lecanii isolates (18) mainly from insects of UK origin; V. lecanii isolates (7) from coffee rust; V. lecanii isolates (11) from scale insects, predominantly tropical; and two isolates of V. ulboatrum. The remaining 16 isolates, mostly from Cordyceps and Torrubiellu infections of tropical forest arthropods, did not fit into any cluster group and all probably represent undescribed anamorphs. A similar pattern was obtained when the electrophoretic properties of catalase isoenzymes were compared. Twelve catalase bands were identified. The taxonomic significance of these findings is discussed.

The analysis of the complete mitochondrial genome of Lecanicillium muscarium (synonym Verticillium lecanii) suggests a minimum common gene organization in mtDNAs of Sordariomycetes: phylogenetic implications

“…Its classification is mainly based on classical taxonomic and morphological characteristics, as is the case for most asexual fungi. Although biochemical and molecular techniques have been used during the last decade (Jun et al, 1991;Roberts et al, 1995;Sugimoto et al, 2003) the genetics of this organism remain still largely unknown. Reports based on the nuclear ribosomal RNA-gene complex (ITS1-5.8S-ITS2 region) and mtDNA, have shown high levels of polymorphisms amongst strains isolated from various geographic regions and hosts, which suggest that the taxonomical status of this fungus should be revised Zare et al, 1999); a task 1087-1845/$ -see front matter Ó 2004 Elsevier Inc. All rights reserved.…”

Verticillium lecani(Zimm.): A potential entomopathogenic fungus

“…is ubiquitous and has a wide host range. It has the ability to develop successfully in several hosts belonging to the Nematoda (Meyer et al, 1990), Arachnida (Jun et al, 1991), and Insecta (Hall, 1981). V. lecanii is also a mycoparasite of rust (Allen, 1982;Spencer and Atkey, 1981) and other phytopathogenic fungi (Raghavendra-Rao and Pavgi, 1977;Askary et al, 1997).…”

Nuclear rDNA phylogeny in the fungal genus Verticillium and its relationship to insect and plant virulence, extracellular proteases and carbohydrases

“…Verticillium fungi have resulted from the inability to recognize the phylogenetic relationships within this group (Jun et al, 1991). Because of this uncertainty, and because we are interested in understanding the genetic basis for the evolution of pathogenicity, it is important to develop a molecular phylogeny of this group that is independent of morphology.…”

“…Thus, the insect pathogen V . lecanii and the nematode pathogen V. chlamydosporium are hyperparasites on other fungi (Leinhos & Buchenauer, 1992). The pathogens of fungi, V .…”